In the past metal corrosion caused by conventional motor fuels such as gasoline was not much of a problem because such hydrocarbon fuels are inherently non-corrosive. However, with the advent of fuels containing alcohols such as gasohol or straight alcohol fuels, corrosion has become a major problem because such fuels are corrosive. It has been reported that this corrosion is due to the presence of acidic contaminants in the fuels such as formic acid. It is almost impossible to avoid such contaminants because they occur in fuel grade alcohols and are also formed in storage as normal alcohol oxidation products.
It is known from U.S. Pat. No. 2,993,772 that alkenyl succinic acids as well as their anhydrides inhibit and/or prevent the deposit-forming tendency of hydrocarbon fuels during combustion and/or modify the deleterious effect of the formed deposits in both leaded and unleaded fuels, particularly in gasoline and jet fuels. The reaction products of long chain alkylene oxides and alkanolamines also are known. For example, Japanese Pat. No. Sho 48[1973]-88135 discloses such products and their use as antistatic agents in ABS resins. It has now been discovered that the combination of monoalkenylsuccinic acids in which the alkenyl group contains about 8 to 30 carbon atoms with certain N-(2-hydroxyalkyl)monoalkanolamines and N-(2-hydroxyalkyl)dialkanolamines provides corrosion inhibiting properties to fuels containing alcohol such as gasohol and straight alcohol fuels.